High frequency electron discharge tube



April 28, 1942. LABlN HIGH FREQUENCY ELECTRON DISCHARGE TUBE 3Sheets-Sheet 1 Filed Feb. 19, 1941 FIG},

IN A AA A AAAA AAAAA -vvv-vvvvvv VYYY INVENTOR EM/LE LAB/N April ZS,1942. E. LABIN HIGH FREQUENCY ELECTRON DIS CHARGE TUBE Filed Feb. 19,1941 3 Sheets-Sheet 2 2s 29 41 35 52 27 as as I INVENTOH EM/LE LAB/N BY1 I ATT NEY Patented Apr. 28, 1942 Emile Labin, New York, N. Y.,assignor to International Standard Electric Corporation, New York, N.Y., a corporation of Delaware Application February 19, 1941, Serial No.379,559

6 Claims.

The present invention concerns structure of electron discharge tubesespecially designed for operation at high frequencies. In particular theinvention provides, according to certain characteristics thereof,arrangements and electrode structures for simple or multiple electrondischarge tubes which permit the convenient application of feedconnections or output connections in the forward transmission lines ofthe several electrodes. In addition the invention also providesarrangements for such connections.

The invention will be described in detail in the following descriptionin connection with several illustrative embodiments represented in theattached drawings, wherein Figs. 1 and 2 represent two simple electrondischarge tube structures incorporating certain features of theinvention;

Fig. 3 shows an end view of these two structures;

Figs. 4, 5 and 6 represent three embodiments of double electrondischarge tubes incorporating certain characteristics of the invention;and

Fig. 7 schematically represents an arrangement of a multiple tubeaccording to the features ofthe invention.

The structure of the electron discharge tube represented in Fig. 1comprises an envelope in which a vacuum is provided and which isconstituted by tubular anode I, closed at one end by a base 2, and aninsulation portion 3 of glass, for example, sealed onto widened portion4 of the anode and joined to a press 5 by a tubulation or invertedannular press 6. Anode l, base 2, widened portion 4, on the one hand,and the portion 3, the presses 5 and 8, on the other hand, may clearlyeach be formed of a single piece or on the other hand may beindependently sealed together.

The lead-in connection of the anode consists, as shown, of a. cylinder Ipressed upon it in intimate electrical and mechanical contact (forexample, pressed on by force and brazed at its ends) which is joined bya conical portion 8 and a cylinder of larger diameter 9.

The grid of the tube consists of a grid of spiral wires or squirrel cageor other form around mounting bars such as represented at In. Thesemounting bars II! are fixed, for example, brazed, onto a piece ll havingthe form of truncated cone terminated at each side in cylindricalportions. Conducting stems l2 extend to and join onto saidpiece on theopposite side from the active portion ID of the grid, said conductingstems being disp s d along the generatrixcs 0 an imaginary cylinder andserving as supporting connections and lead-out connections which passthrough the annular press 6. On the outside of the tube these stems l2are fixed on the peripheryofa real conductive cylinder l3 which iscoaxial with cylinder [9 of the anode. The diameters of the cylinders 9and I3 are the same ratio as the diameter of the anode I and theimaginary surface of grid in. The joiningsurfaces Band ,although shownas truncated cones, are, so far as possible, formed in such manner as tofollow the imaginary curves of junction which are theoretically requiredto preserve the uniform gradient between the structures of the anode andthe grid.

The cathode structure consists of a filament l4 spirally wound, forexample, on an imaginary cylinder coaxial to the cylinders of the gridand anode and supported and fed in known manner by two stems I5 and I6which pass through the press 5. On the outside of the envelope the twostems l5 and [6 are placed as shown within the inside of a conductivescreen I! in such manner as to form a shielded pair coaxial to theconnecting cylinders I3 and 9 of the grid and anode. Here, also, thediameters of this screen I! and of the grids cylinder I 3 are in thesame ratio as the diameter of the imaginary cylinders l0 and M of theactive parts of the grid and filament. This ratio, as well as thepreviously mentioned one, is preferably provided in such a way as tohave a value which is well known in the art of coaxial transmissionlines. In this way the feeding of the electron discharge tube circuit iseffected by means of a three conductor coaxial line 9, I3, H, as seen inplan view in Fig. 3.

In the embodiment shown, an end cap I8 is provided on the grid to playthe part of a screen between the grid cathode space of the base 2 of theanode. With respect to the assembly, the cathode and grid electrodes arefirst assembled in insulating portion 3 of the envelope, while saidassembly is mounted. Then when the assembly is mounted in anode I, onecan thus determine with precision the value of the capacity between base2 and theanode and screen l8 of the grid.

The structure represented in Fig. 2 is in general analogous to Fig. 1,especially in so far as the arrangement of the lead-out connections fromthe electrodes in the form of a three conductor coaxial line isconcerned. In this figure,

the same reference characters as shown in Fig. 1 are applied to thecorresponding elements. j.

QW Q ppo w o t e g d are extended arrangement of such a double tube.

and bent in such a way as to extend to and join electrically andmechanically around a metal plate provided with peripheral brim 20 forsealing to insulation portion 3 of the envelope and for electrical andmechanical attachment of the feed cylinder l3. Also, conductors l5 andI6 supporting and feeding the filament pass through two sleeves 2| and22 of larger diameter which form part of theplate I9 and are sealed ininsulating sleeves 23 and 24, which themselves are sealed to theconductive sleeves 2| and 22 extended to such a point as to avoiddischarge along the insulation between the connections of grid andcathode.

At the other end of the tubeis shown an anode structure different fromthat of Fig. 1. In this tube anode I is open at both ends and is sealedonto a balloon 25 made of glass, for example, and the outside cylinder 1is extended all around this balloon, as shown at 26, whether it be by anexternal metalization of the balloon or by a continuous metal envelopeor, by a metallic screen or trellis. Such an end structure has theadvantage compared to that of' Fig. 1, that. the

assembly .of the tube is facilitated. For before sealing the balloon 25tools. may. be passed through! anode L. The capacity between the screenof gridlfi'and the base 26' of the anode is then not known, but is madevery small in consequence of the relatively large spacing between saidscreen IB and the metallic coating926.

One sees that the section of Fig. 3 can again be consideredas applicableto the structure of Fig. 2, aside from the fact that the press 5 must bereplaced by two insulating sleeves. 23 and 24. It is clear that the,anode-may be cooledif desired-in any suitable manner, eithernbycirculatticn of-rcooling' fluid within a ski-rt which; is pro:- videdfor. this; purpose around this; anode, or simply by providing on thesurface ofjcylinder 1 little cooling wings. The anode I, may, moreover,consist either of ametal plate which is beatenout or shaped in someother-manner or a bar -which;isl hollowed out;so asto contain the otherelectrodes.

In addition,itisjclea-r that in the structures, as well as in thosehereafterto be described, additional electrodes, for example, grids,could be added to the tubes-without departing from the In 'thecase whereanode l is formedbyasolid bar, hollowed out to contain theother=electrodes-,

there is no need for a drawing to explain the It is sumcient toconsider, for example, one of the Figs. 1 and,.2 and to complete it-by astructure which issymmetrical with respect to a plane perpendicular tothe longitudinal axispassingnear the end'of the anode. However, such astructure will necessitate: pumping operations; unless a passage beestablished through the solid portion of the bar which serves asananode.

A similar arrangement could clearly be adopted with a thin walled anode,such as represented in Figs. 1 and 2, the two end structures beingsufiiciently spaced from each other. However, it may be advantageous incertain cases to abandon the three-conductor coaxial output line and usein its place two or several transmission lines extending from theelectrodes of the arrangement. Figs. 4, 5 and 6 show three examples ofsuch structures.

In the structure of Fig. 4, the cylindrical anode 21 is open at its twoends and on these ends are sealed insulated balloons 28 and 29 whichmay, for example, be of glass. In cylinder 2'! there is fixed,iorinstance by brazing, a short conductive tube 39 on, the open end ofwhich is sealed insulating balloon 3|. On the inside of the air tightenvelope thus formed, there is disposed a grid structure consisting ofan elongated cylinder 32 coaxial to anode 21' and supported at itscenter, by a stem 33, serving as a lead-irr conductor. Stein 33. passes,coaxially; through sleeve 30 andp'asses out of balloon 3! throu h seal34, for instance, a. direct glassmetalsea-l asshown. At each end of tube33 there are fixed, for example by-b'raz-ing, a'certainnumber of posts35, 36, parallel to the generatrixes of thecylinder 33 on which arewrapped the grid" threads, not shown. On the inside of thesegrids andalong their length aredisposed filamentary cathodes 3'! andflfi,respectively, carried by supporting and lead-in stems 39'and' 40 whichpass through the balloons 28; and 29 through seals, such as shown forexample at 4-! and: 42. Screens may, as shown at 43 and; 44.oe-provicled at the ends of the'grids-a'i and 38.

Two coaxial lines may thenbe provided at the two ends of the structurein the manner shown in Figs- 1 and 2 by means of cylinders attached toanode 2'! and extending coaxially with respect to the axis of thecomplete structure, the other conductor of-these coaxial linesbeingconstituted by cylinders forming the screen for the lead-inconductors of the cathodes. A third coaxial line may, if desired, beprovided betWeen the anode sleeve 30 and the grid conductor 33 in thesame way. A jacket for water or other cooling fluid,- may be providedaround the anode. The continuityof. the-gridstructure avoidsallvundesirable electron couplings between the ends-of the filaments andthe anode.

In such a double structure, it may nevertheless be desirable to be ableto Withdraw energy from the grid. Consequently, asshown in. Fig.

. 5, one may provide on the anode 21 two other cylindrical sleeves 45and 46, schematically dis- DOSGd'OIl each side of the axis. of thesleeve 30 and onthe other side. of the anode. These sleeves 45 and 48carry sealed on to them insulating balloons 41 and idthrough which passthe lead-in conductors of. grids 4 9 and, 50, by means of seals 5| and52, for example. These conductors 49 and 50 may constitute. a parallelwire line. The rest of the structurebeing identical to Fig. 4 will notbe described in detail and the, same numerical references are assignedto corresponding elements, as. is the case also in the structure of Fig.6.

In this Fig. 6, however, the two balloons28 and 29 attwo ends of theanode?! are no longer passedthrough by the lead-outs of the filaments ofthe two active structures. Thesestructures operate in the case of thisfigure with filaments 53 and 54 in series, fed by conductors 55 and'56which extend longitudinally on the. inside of, the

grid cylinder and pass out at right angles, as shown through aninsulating balloon 51 sealed to a fourth cylindrical sleeve 58 of heanode 2i. This lead-out is effected in the middle of the tube betweenthe lead-out conductors of the grid.

Still another utilization of the structures described in the inventionmay be visualized for tubes which are no longer double but multiple. Inthis case schematically represented in plan view in Fig. 7 a certainnumber of simple structures are schematically assembled around an axis.Such an arrangement requires no additional description, beingself-explanatory in accordance with the descriptions of the precedingfigures.

Although the invention has been described in the case of certainparticular examples of embodiments, it is clear that it is not limitedthereto in any respect, but is, on the contrary, susceptible of numerousmodifications and adaptations without departing from the domain of theinvention. In particular all of the appropriate structures of filamentsand grids may be used in devices incorporating the characteristics ofthe invention.

What is claimed is:

l. A high frequency vacuum tube arrangement comprising a cylindricalanodeforming a part of the envelope, a grid electrode assembly arrangedon a cylindrical surface of a given diameter arranged concentrically ofsaid anode, a concentric transmission line externalof said envelope,means interconnecting said outer conductor and said anode, and meansinterconnecting said inner conductor and said grid, each of saidinterconnecting means comprising a generally conical tapering member,one of said conical members being disposed within the other of saidconical members, whereby a substantially uniform gradient between theanode and the grid structures is obtained.

2. A high frequency tube arrangement according to claim 1 in which therespective radii of each of said members at any given point along theaxis of said tube bears substantially the same ratio as the ratio of therespective radii of the conductors of said concentric transmission line.

3. A high frequency tube according to claim 1, further comprising acathode having a cylindrical surface concentrically arranged within saidgrid electrode assembly and means for energizing said cathode,comprising a shielded conductor pair, the shield of said pair beingarranged concentrically within said inner conductor and havingsubstantially the same diametral ratio to said iiuier conductor as saidcathode cylinder has to said cylindrical surface.

A vacuum tube structure comprising an anode of substantially cylindricalform, glass bulbs sealed at each end of said anode, a tubular gridsupport mounted concentrically within said anode, a set of grid wires ateach end of said tube cooperating with said anode, cathode structuresarranged concentrically of said grid wire set and supported by leadsthrough said glass bulbs, a further glass seal substantially at alongitudinal midpoint on the periphery of said anode, and a rod fastenedsubstantially at the center or" said tubular support and extendinggenerally radially of said anode and supported in said further glassseal to maintain said tubular support in position.

5. A vacuum tube structure according to claim 4;, further comprisingoutput leads comprising rods connected at one end to symmetricallyspaced points on said tubular support, and lateral extensions in saidanode concentrically arranged outside each of said leads.

6. A vacuum tube structure according to claim further comprising cathodeenergizing leads arranged within said tubular support, said tubularsupport and said anode being provided with an opening substantiallymid-way along their lengths, and means for supplying the filamentheating current to said cathode energizing leads extending through saidopenings.

EMILE LABIN.

